Heat treatment effect of T91 maxtensitic steel on liquid metal embrittlement

摘要

The sensitivity of liquid metal embrittlement of the T91 martensitic steel is investigated with small punch tests at 300 degrees C in air and in lead bismuth eutectic (LBE). The material was studied in six tempering conditions corresponding to different values of hardness. An effect of LBE has been observed for all the materials excepted for T91 steel tempered at 750 degrees C, the more ductile material. In high strength materials (T91 steel as quenched, tempered at 600 degrees C or 500 degrees C), a ductile to brittle transition is induced by liquid metal, confirmed by the observation of brittle fracture. In relative high strength materials (tempered at 650 degrees C and 700 degrees C), LBE promotes a decrease in mechanical properties and a reduction of the ductility of materials, with a mixed ductile and brittle fracture. (C) 2008 Elsevier B.V. All rights reserved.